Handle lock for safe doors and the like

ABSTRACT

A handle lock for use on safe doors and the like is provided including a lock shell, a lock plug, a shaft and a handle. The lock shell is formed with a smooth cylindrical outer surface and a central throughbore adopted to receive the lock plug. To provide for selective rotation of the lock plug within the lock shell, the lock plug includes tumbler means which engage with longitudinal lock grooves formed in the lock shell. A shaft connects the lock plug to a crank which translates the rotary motion of the lock plug into the operation of the door latches. The handle is provided with a mounting throughbore formed with an internal annular ledge. The annular ledge has multiple connecting splines which interlock with complemental connecting splines on an annular flange on the lock plug when the lock plug is inserted into the mounting throughbore. The sides of the complemental positioning splines are tapered so that they will slide out of engagement if a significant force is applied to the handle while the tumbler means are engaged with the locking grooves. The handle is also provided with positioning splines formed on the rear face of the mounting throughbore. These positioning splines engage with complemental positioning splines formed on the face of the lock shell when the handle is turned into either the open or closed position.

This is a continuation of application Ser. No. 8/301,804 filed on Sep.7, 1994, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the invention

This invention relates generally to the field of combinating tumblerlocks, and more particularly to tumbler locks used on safe doors and thelike.

2. Description of the Prior Art

There are many combinating tumbler handle locks in the prior art whichcan be used on a safe door or the like. However, many of these havedrawbacks which make them undesirable.

A common problem with combinating tumbler locks is that they arevulnerable to being forced open by individuals not possessing a key.When the handle lock is used in conjunction with a combination lock on asafe door, this could create undesirable security problems. For example,in an office environment it is often inconvenient for employees to dialthe combination each time they wish to open the safe. Therefore,frequently, the safe's combination lock is unlocked at the beginning ofthe day and for the remainder of the day the safe is opened and closedusing only the key-actuated handle lock. While this arrangement may beconvenient, it places the contents of the safe in a vulnerable position.With typical combinating tumbler handle locks, the handle is rigidlyconnected to the lock plug and if a significant force is exerted on thehandle when the tumblers are engaged with the lock shell the tumblersmay shear within the lock shell. Once the tumblers have sheared, thelock plug might rotate freely within the lock shell and the safe can beopened without the use of the key. Worse yet, application of such aforce may result in a jamming or breaking of the handle, resulting inlockout.

Another common problem with combinating tumbler handle locks is that thehandle rotates loosely after the key has been inserted in the lock. Thisloose rotation can result in difficulty in locating the open and closedpositions of the handle lock. In addition, the loose rotation may makeit difficult to keep the handle accurately aligned in the open andclosed positions after the key has been inserted. Thus, this looserotation makes these locks inconvenient to use.

SUMMARY OF THE INVENTION

Accordingly, it is a primary object of the present invention to overcomethe deficiencies in the existing combinating tumbler handle locks byproviding a tumbler handle lock that cannot be forced open through theexertion of a significant turning force on the handle when the tumblersare engaged with the lock shell.

It is an additional object to provide a tumbler handle lock that allowsthe handle to be accurately aligned and held in either the open orclosed position when the key is inserted.

It is an additional object to provide a tumbler handle lock that has asimple construction and a low manufacturing cost.

In accordance with these and other objects, there is provided a novellock construction primarily for use on safe doors and the like. Thehandle lock primarily consists of a lock shell, a lock plug, a shaft anda handle. The lock shell is formed with a smooth cylindrical outersurface and a central throughbore adapted to receive the lock plug. Thelock plug includes tumbler means which engage with longitudinal lockgrooves formed in the lock shell in order to provide for selectiverotation of the lock plug within the lock shell. A shaft connects thelock plug to a crank. Several links are pivotally connected to the crankand to the door latches in order to translate the rotary motion of thelock plug into the operation of the door latches. The handle is providedwith a mounting throughbore formed with an internal annular ledge. Toprovide for the connection of the handle to the lock plug, a breakawayinterlocking connection is used. The annular ledge has multipleconnecting splines which interlock with complemental connecting splineson an annular flange on the lock plug when the lock plug is insertedinto the mounting throughbore. The sides of the connecting interlockingsplines are tapered so that they will cam and slide out of engagement ifa significant force is applied to the handle when the tumbler means areengaged with the locking grooves. To provide for accurate positioning ofthe handle in the open and closed position, the handle is provided withpositioning splines formed on the rear face of the mounting throughbore.These positioning splines engage with complementary positioning splinesformed on the face of the lock shell when the handle is turned intoeither the open or closed position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the handle, lock plug and shaft of oneembodiment of the handle lock.

FIG. 2 is a perspective view of the lock shell of one embodiment of thehandle lock.

FIG. 3 is an environmental drawing showing the handle lock in itshousing alongside a combination lock in one embodiment of the handlelock.

FIG. 4 is a section view of the handle, the lock shell and the lock plugwithout the shaft in one embodiment of the handle lock.

FIG. 5 is an exploded perspective view of one embodiment of the handlelock.

FIG. 6 is an end elevation view of the key slot end of the lock plug ofone embodiment of the handle lock.

FIG. 7 is an elevation view of the handle of one embodiment of thehandle lock.

FIG. 8 is a section view taken substantially along line 8--8 in FIG. 6showing one of the connecting splines formed on the lock plug in oneembodiment of the handle lock.

FIG. 9 is a section view taken substantially along line 9--9 in FIG. 7showing one of the complementary connecting splines formed on the handleof one embodiment of the handle lock.

FIG. 10 is an end elevation view of the lock shell in one embodiment ofthe handle lock.

FIG. 11 is a fragmentary side elevation view of the shaft in oneembodiment of the handle lock.

FIG. 12 is an environmental drawing showing the crank and link mechanismthat controls the operation of the door latches in one embodiment of thehandle lock.

FIG. 13 is a fragmentary section view showing the connection between theshaft and the crank in one embodiment of the handle lock.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

While the invention will be described in connection with a particularpreferred embodiment, it will be understood that it is not intended tolimit the invention to that particular embodiment. On the contrary, itis my intention to cover all alternatives, modifications andequivalences that may be included within the spirit and scope of theinvention as defined by the appended claims.

Turning to the drawings, there is shown in FIGS. 1 and 2 a handle lock10 manufactured in accordance with the present invention. As can be seenfrom these figures, the lock is a simple construction consisting ofrelatively few parts. These parts include a lock shell 20, a lock plug30, a shaft 40 and a handle 50.

The lock shell 20 has a substantially smooth cylindrical outer surfaceand a central throughbore 22. The central throughbore 22 is adapted toreceive a lock plug 30. In addition, to facilitate mounting of the lockshell 20 onto a safe door or the like, the lock shell 20 incorporatesmultiple mounting posts 24. One skilled in the art will appreciate thatseveral other means of mounting the lock shell 20 on a safe door or thelike could be used.

To provide for selective rotation of the lock plug 30 within the lockshell 20, the handle lock 10 includes tumbler means 32 disposed withinthe lock plug 30 which engage with longitudinal lock grooves 26 in thelock shell 20. As shown in FIG. 5, the tumbler means 32 are disposed ina key slot or tumbler receiving opening 34 located in the lock plug 30.In the present embodiment, the tumbler means 32 are conventionalcombinating tumblers which are paired for use with a double bitted key80. In a conventional fashion, the tumblers 32 are normally biasedoutward beyond the perimeter of the lock plug 30 and into engagementwith the longitudinally running locking grooves 26 in the lock shell 20.As shown in FIG. 10, the locking grooves 26 are separated by 180 degreesaround the circumference of the lock shell 20. When the tumblers 32 arein the outwardly biased position and are engaged with the longitudinallocking grooves 26, the lock plug 30 cannot rotate within the lock shell20. However, when the tumblers 32 are actuated by a properly codeddouble bitted key 80, they withdraw into the tumbler receiving opening34 until they are flush with the exterior surface of the lock plug 30.When in this position, the tumblers 32 are no longer engaged withgrooves 26 and the lock plug 30 is free to rotate within the lock shell20. The key 80 is inserted through a key slot 34 which is centrallylocated on the front end of the lock plug 30.

As depicted in FIG. 5, the rear section of the lock plug 30 contains arectangular opening 36 for receiving one end of a shaft 40. In theillustrated embodiment, the shaft 40 is secured in the rectangularopening by a pin 42. As shown in FIG. 12, the opposite end of the shaft40 is connected to a crank 60 which is part of the mechanism forcontrolling the latches on the safe door or the like. As shown in FIG.11, the shaft 40 is comprised of two sections of differingcross-sectional areas with a shoulder 42 separating the two sections.The section of the shaft 40 that is connected to the lock plug has alarger cross-sectional area than the section that is threaded. As shownin FIG. 12, the crank 60 contains a central throughbore 62 for receivingthe threaded end of the shaft 40. The shaft 40 is formed with theshoulder 42 positioned such that when the crank 60 is properly securedon the shaft 40 by a conventional nut 46 and washer 44, the crank 60abuts against the shoulder 42.

To provide for the opening and closing of the safe door or the like, oneend of four separate links 64 are pivotally connected to the crank 60,as shown in FIG. 12. The opposite end of each of the links 64 ispivotally connected to one of four separate door latches 66. The doorlatches 66 are contained in horizontal slides 68 which are mounted tothe safe door or the like 69. The links 64 and horizontal slides 68translate the rotation of the crank 60 into a linear motion of the doorlatches 66. Depending on the direction of the rotation of the crank 60,the links 64 will either push the door latches 66 into engagement withcomplementary locking slots on the body of the safe or the like or pullthe door latches 66 out of engagement. Thus, the rotation of the lockplug 30 within the lock shell 20 operates the door latches 66 due to therigid connections between the lock plug 30 and the shaft 40 and theshaft 40 and the crank 60.

Returning to FIG. 5, a handle 50 is connected to the front portion ofthe lock plug 30 to control the rotation of the lock plug 30 within thelock shell 20. The handle 50 is formed with a stem portion and amounting throughbore 52 which is adapted to receive both the lock plug30 and the lock shell 20. As depicted in FIG. 4, the mountingthroughbore 52 has a front section with a first smaller diameter and arear section with a second greater diameter. The front section of themounting throughbore 52 is adapted to receive the key slot 34 end of thelock plug 30 so that the key slot 34 is flush with the outside surfaceof the handle 50. As shown in FIG. 7, there is an annular ledge 54incorporating a series of connecting splines or grooves 56 at thetransition between the front and rear sections of the mountingthroughbore 52. In the illustrated embodiment there are six connectingsplines 56 equally spaced around the annular ledge 54.

To secure the handle 50 to the lock plug 30, an annular flange 38 on thelock plug 30 is formed with connecting splines 39 which are complementalto the connecting splines on the handle, the complemental connectingsplines on the lock plug illustratively being a series of connectingdetents. As seen in FIG. 6, there are six complemental connectingsplines 39 equally spaced around the annular flange 38. The connectingsplines 56 in the handle and the complemental connecting splines 39 onthe lock plug fit together in an interlocking relationship to form abreakaway interlocking connection between the handle 50 and the lockplug 30. Although this embodiment shows the connecting splines andcomplemental connecting splines as grooves and detents, respectively,the opposite could be true, or other spline configurations could beused. According to the invention, a breakaway interlocking connection isused so as to provide breakaway of the handle upon application of asubstantial force to the handle. As shown in FIGS. 4 and 5, theconnecting splines 56 and the complemental connecting splines 39 areheld together in their interlocking relationship by a thrust washer 55,a conventional washer 57 and a hairpin 58 which is contained in a slot59 in the side of the handle mounting throughbore 52.

While the handle 50 will remain connected to the lock plug 30 duringnormal rotation of the handle 50, the connection is adapted to breakaway if someone attempts to forcibly open the handle lock 10 withoutusing the key 80 by applying a substantial force such as might otherwiseshear the tumblers, for example. As shown in FIG. 9, the connectingsplines 56 on the annular ledge 54 are formed with slightly taperedsides. Likewise, the complemental connecting splines 39 on the annularflange 38 also have slightly tapered sides as shown in FIG. 8. Theseslightly tapered sides allow the connecting splines and complementalconnecting splines forming the breakaway interlocking connection toslide out of their interlocking arrangement by a camming action when asignificant turning force is applied to the handle 50 when the tumblers32 are engaged with the locking grooves 26. The tapered sides are formedso that they are steep enough to ensure that the connecting splines andcomplemental connecting splines remain interlocked during normalrotation of the handle 50. However, the sides are sufficiently taperedto ensure that the breakaway interlocking connection will break awaybefore a force is applied that is sufficient to shear the tumblers 32inside the locking grooves 26 absent this breakaway feature.

As shown in FIGS. 2 and 4, the front end of the lock shell 20 is formedwith an annular collar 28. The annular collar 28 is adapted to beinserted into the rear section of the handle mounting throughbore 52.The annular collar 28 prevents the handle 50 from moving laterallyrelative to the lock shell 20. As depicted in FIG. 4, when the annularcollar 28 is fully inserted into the mounting throughbore 52, an annularshoulder 29 located adjacent to the annular collar 28 abuts against therear lip 53 of the mounting throughbore 52.

In order to accurately align and hold the handle 50 in the open andclosed positions, the annular shoulder 29 of the lock shell 20 is formedwith positioning splines 25 illustratively in the form of multiplegrooves. Additionally, as shown in FIG. 7, the rear lip 53 of themounting throughbore 52 is provided with complemental positioningsplines 51 illustratively in the form of multiple detents. In theillustrated embodiment, there are three positioning splines 25 separatedby 120 degrees around the circumference of the annular shoulder andthree complemental positioning splines 51 separated by 120 degreesaround the circumference of the rear lip. The complemental positioningsplines 51 and the positioning splines 25 are arranged so that they willengage when the handle 50 is rotated into either the open or closedposition. Both the positioning splines 25 and the complementalpositioning splines 51 are formed with tapered sides so that they caneasily slide into and out of engagement when the handle 50 is turned.

The handle lock described herein thus provides a breakaway interlockingconnection between the lock plug and the handle that preventsunauthorized entry by means of shearing the tumblers through forcibleturning of the handle. Further, the use of engageable grooves anddetents on the lock shell and handle allows the lock to be accuratelyaligned in the open and closed positions.

I claim as my invention:
 1. A handle lock for a safe door or the likecomprising in combination:a lock shell having a substantially smoothcylindrical surface, a central throughbore, including longitudinallocking grooves, an annular collar and an annular shoulder; a lock plugfor selective rotation within said lock shell and having a front sectionincluding a tumbler-receiving opening, a key slot centrally located onan end and an annular flange and a rear section including a shaftreceiving means; a handle for controlling rotation of said lock plug andhaving a stem portion and a mounting throughbore portion for receivingsaid lock shell annular collar and said lock plug; said mountingthroughbore having a front section with a first smaller diameter, a rearsection with a second greater diameter and an annular ledge between saidfront and rear sections; a shaft connecting said lock plug to a doorlatch actuation means; a tumbler means disposed in saidtumbler-receiving opening for selective engagement with saidlongitudinal locking grooves, said tumbler means including coding foractuation by a properly coded key for disengagement from said lockinggrooves to allow for said selective rotation of said lock plug; abreakaway interlocking connection between the lock plug and the handle,wherein said mounting throughbore annular ledge is formed withconnecting splines and said lock plug is formed with complementalconnecting splines on said lock plug annular flange, the connectingsplines and complemental connecting splines being mutually engageable inorder to secure said handle to said lock plug during turning of saidhandle and being formed with slightly tapered sides whereby saidconnecting splines and said complmental connecting spines slide out ofengagement and allow said handle to rotate relative to said lock plugupon application of an excessive force to said handle while said tumblermeans are engaged with said locking grooves; means for biasing saidmounting throughbore annular ledge and said lock plug annular flange,and thereby said connecting splines and said complemental connectingsplines, into engagement; and positioning splines formed on said rearface of said mounting throughbore and complemental positioning splinesformed on said lock shell shoulder, said positioning splines andcomplemental positioning splines being adapted such that saidpositioning splines and complemental positioning splines are mutuallyengaged when said handle is in either the open or closed position inorder to maintain the handle in that position and said positioningsplines and complemental positioning splines are mutually disengagedwhen said handle is being rotated.
 2. The handle lock according to claim1, wherein said complemental connecting splines on said lock plugannular flange and said connecting splines on said mounting throughboreannular ledge are formed with slightly tapered sides whereby saidconnecting splines and said complemental connecting splines slide out ofengagement upon application of a substantial force applied to saidhandle while said tumbler means are engaged with said locking grooves.3. The handle lock according to claim 1, wherein said shaft is formedwith two sections of differing cross-sectional areas separated by ashoulder and said shaft is adapted so that said door latch activationmeans abuts against said shoulder when said door latch activation meansis connected to said shaft.
 4. The handle lock according to claim 1,wherein said lock shell is formed with multiple mounting posts on theend opposite said annular collar and said annular shoulder.
 5. Thehandle lock according to claim 1, wherein the biasing means includes ahairpin, a washer and a thrust washer, and wherein said handlethroughbore includes a slot, the hairpin being receivable in said slot,said thrust washer and washer being disposed around the lock plug andmaintained in position by the hairpin for biasing the connecting splinesand complemental connecting splines into engagement.